Tubular boiler



D. MACDONALD.

TUBULAR BOILER.

APPLICATION FILED SEPT. 20. 1919.

1,365,713. Patented Jan. 18,1921.

2 SHEETS-SHEET l.

INVENTOR WITNESSES D. MACDONALD.

TUBULAR BOILER.

APPLICATION FILED SEPT.20, 1919.

Z SHEETS SHEET 2.

Patented Jan. 18, 1921.

UNITED STATES PATENT OFFICET DUNCAN MACDONALD, 0F PITTSBURGH, PENNSYVANIA.

TUBULAR BOILER.

Application filed September 20, 1919.

of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Tubular Boilers, of which the following is a specification.

My invention relates to steam boilers and comprises a boiler of the flash type peculiarly adapted for use in steam motor vehicles. The object of my invention is to provide a water tube boiler which will be economical in first cost and in operation, will efficiently transmit the burner heat to the water it contains, and can be made in sections so as to be easily assembled in manu facture or disassembled for repairs.

My boiler is illustrated in the accompanying drawings in which Figure 1 is a plan of the whole boiler; Fig. 2 is in part an elevation and in part a vertical section through the boiler; Fig. 3 is'a fragmentary plan and section of the upper headers and their connections and Fig. 4 is a horizontal section through one of the vertical tubes on line 4--4 of Fig. 2.

The heating tubes 1 are arranged in a series of concentric vertical rows. The ends of tubes 1 are welded to the walls of horizontal headers 2 and 2. Each header is bent into a semicircle and each of its ends is welded to a hollow connection member A complementary semicircular header has its ends welded to the opposite sides of members 3. Each section of my boiler comprises an upper pair and a lower pair of these semicircular headers with the connections 3-3 and heating tubes 1-1. A number of such sections are assembled by alining members 33. The sectional part of Fig. 3 illustrates the manner in which one end of each member is adapted to fit within the opposing end of another member and to form a tight joint therewith.

In the center of the boiler is a standpipe 4 about which the boiler sections are arranged. Passing through all of members 3-3 on one side of standpipe 4 and through 1 one wall of the latter is a staybolt 5 which is small enough in diameter to permit free circulation of water between it and the inner walls of members 3-3. The inner end of each staybolt 5 is secured by a spider nut 6 provided with spaces to permit the entrance and exit of circulating fluids.

Tubes 1 are not perpendicular but are in- Speciflcation of Letters Patent.

Patented Jan. 18, 1921.

Serial No. 325,139.

clined. The upward inclination of tubes 1 in the outer section is from left to right and the upward inclination of those in the next section is from right to left. The direction of inclination of tubes 1 in the remaining sections alternate for each section.

To increase the proportionof tube surface to the volume of water contained, I flatten each tube from a short distance above the lower header to a'pomt approximating the water level in the boiler, giving the tube between these points the shape shown in Fig. 4. In assembling these flattened tubes with the headers, I prefer to turn their flattened sides horizontally so as to present their broader surface to the upwardly moving 1 gases which rise from the burner (not shown) placed beneath the boiler. Instead of passing straight up, the gases will be diverted by the inclined tubes and forced into a tortuous path between the latter which will allow more time during the passage for the heat to be extracted and absorbed by the water. The inclined tubes also offer a greater lengthto the heating gases than would be afforded by vertical tubes in a boiler of similar height.

The boiler water supply is connected to the standpipe 4 at 7 and the steam outlet is from the standpipe 4 at 8. This outlet is through a superheating coil 9 which leads the steam to the engine to be supplied by the boiler.

The circular arrangement and the alternate inclination of the rows of water tubes 1 permit the extraction of a larger proportion of the heat than is usually obtained and result in an economical disposition of the parts which is especially valuable in automobile construction. The sectional assembly enables the heating tubes and horizontal headers to be grouped in convenient units and in the event of repair or replacement it is not necessary to dismantle the whole "boiler to get at the defective tubes. It is possible to remove an entire section of the boiler and, by replacing the removed members 33 with dummy members without side openings, to retain complete circulation. While the steam then generated in the boiler will be less than the capacity of the complete boiler, it will, nevertheless, be an emergency supply which may often prove valuable.

I have shown headers 2 and 2 as semicircular arcs which require two series of connecting members 3-3 and provide two passages for the flow of water and steam from the headers to each other and to standpipe 4:. It would be within the scope of my invention to decrease the arc of the headers and insert more of such circulatory passages or to eliminate one of those shown and make each header a nearly complete circle.

I refer to the inclined tubes 1 as heating tubes simply to facilitate description and reference. It will be understood that while tubes 1 provide the larger part of the heating surface, the surface of the connecting members, the standpipe, the circular headers and especially the superheating coils also serve to transmit heat to fluids contained therein.

I claim 1. In a boiler, a central standpipe, a series of concentric headers arranged about said standpipe, a second series of concentric headers arranged about said standpipe and spaced from said first series, a plurality of tubes connecting corresponding headers in each of said series; each of said headers having an integral header connecting member provided with oppositely disposed openings and staybolts disposed radially of said standpipe, gripping one Wall of same, passing through all of said connecting members in each series of headers on that side of said standpipe and uniting said headers in a sectional, circulatory system.

2. In a boiler, a central standpipe, an upper and a lower series of headers arranged in concentric circles around said standpipe, tubes connecting the upper with the lower headers, means internally connecting the up per headers together and to said standpipe and means connecting the lower headers together and to said standpipe; each of said means being removably connected to its adjacent means and to said standpipe so that any pair of corresponding upper and lower headers, with their connecting tubes may be individually removed and replaced.

3. In a sectional boiler, upper and lower concentric headers, inclined heating tubes connecting said headers, each flattened from a point near its bottom to a point near the water level to be maintained in the boiler and cylindrical throughout the remainder of its length.

In testimony whereof, I have hereunto subscribed my hand this 19th day of Sep tember, 1919.

DUNCAN MAGD ONALD. 

